Haflinger Engine Wanted

I am looking for the original engine with engine no. 5367822 for my Haflinger, which was originally delivered to GB in 1974. The engine was once replaced for an unknown reason. The previous owners do not remember anything relevant about the remains of this engine, but since the Haflinger world is small, especially in Great Britain, I thought that there is a chance that the engine (or at least the crankcase) is floating around somewhere with an other enthusiast.

thanks for your replies. Maybe I was not clear enough, the previous owners don't know why the engine was replaced and the earliest owner I could track down (and who probably did the job) has sadly deceased. The Haflinger was originally delivered to the MoD and the original registration was removed when it was sold to private hands. The Haflinger probably never got a new registation.